Snap locking structural joint assembly

ABSTRACT

A snap-locking structural joint assembly and method of assembling same comprising an elongate structural connecting member having longitudinally extending channel means in at least one side thereof and a fastening clip means having flange means thereon adapted to be received in said channel means to secure said fastening clip to said elongate structural member, and locking means operatively associated with opposite, spaced apart legs of said fastening clip means to lock said fastening clip means to a second elongate structural member for releasably joining said second elongate structural member to said first elongate structural member.

United States Patent [191 Zimmer Dec. 11, 1973 SNAP LOCKING STRUCTURALJOINT ASSEMBLY [76] Inventor: Ernest C. Zimmer, Rte. 2, PD. Box

307, Wellsburg, N.Y.

[22] Filed: June 4, 1971 [21] Appl. No.: 150,002

[52] U.S. C1. 287/54 C, 52/645, 287/2092 C,

52/665 [51] Int. Cl. ..L F161) 7/22 [58] Field of Search 287/54 A, 54 B,54 C,

287/l89.36 H, 189.36 R, 20.92 D, 20.92 C; 52/645, 656, 665, 475

[56] References Cited UNITED STATES PATENTS 3,561,801 2/1971 Chiu287/l89.36 H 3,485,519 12/1969 Chiu 287/189.36 H 3,642,310 2/1972 Hudson287/54 A 3,061,055 10/1962 Nijhuis 287/l89.36 H 3,458,052 7/1969 Kann287/54 A X 3,612,585 10/1971 Mayr 287/54 A X Primary Examiner-James R.Boler Assistant ExaminerWayne L. Shedd Att0rneyShoemaker & Mattare [57]ABSTRACT A snap-locking structural joint assembly and method ofassembling same comprising an elongate structural connecting memberhaving longitudinally extending channel means in at least one sidethereof and a fastening clip means having flange means thereon adaptedto be received in said channel means to secure said fastening clip tosaid. elongate structural member, and locking means operativelyassociated with opposite, spaced apart legs of said fastening clip meansto lock said fastening clip means to a second elongate structural memberfor releasably joining said second elongate structural member to saidfirst elongate structural member.

17 Claims, 16 Drawing Figures PMENTE[1 3.778.175

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23 INVENTOR 5 ERNEST G. ZIMMER BY Mm ATTORNEYS INVENTOR ERNEST C. ZIMMERATTORNEXB PATENIEU min! 1 I913 SHEUBUFI INVENTOR ERNEST C. ZIM M ERATTORNEYS PATENTEI] Bill] 1 I973 SHEET b 0F 4 FIG/4.

FIG/3.

INVENTOR ERNEST c. ZIMMER MW w? 3mm ATTORNEYS SNAP LOCKING STRUCTURALJOINT ASSEMBLY BACKGROUND OF THE INVENTION The present invention relatesto a new and novel snap-locking structural joint assembly which is lightweight in construction and which, more particularly, relates to amanually assembled type of structural joint interconnection.

The invention is especially suitable for assembling various structuralassemblies, such as canopies and awnings; storage or utility buildings;wall and office partitions; truck bodies; portable swimming pool wallconstructions; camper tops; motor homes; mobile homes; car ports;skirting and accessories; fencing; buildings, such as patio lockers,storage sheds and shelters; shelving and storage racks; furniture; cartop carriers; home remodeling equipment, such as installation apparatusfor suspended ceilings and the like; toys; ornamental iron work, and soforth. It is important with these applications that the elements bequickly and easily assembled and once in assembled position positivelylocked in place yet at the same time permitting them to be separatedwhen and if desired.

With the present invention, a snap-locking fastening clip means isprovided which enables the various structural elements to be readilyassembled in positively locked together relationship and yet wherein theelements may be quickly and easily disassembled if desired.

- In general the inventioncomprises a snap locking structural jointassembly including a first elongate structural member having recessmeans therein and fastening clip means having a pair of oppositelydirected yieldable projections thereon received in said recess meansholding said clip means to said structural member in predetermined axialposition. Releasable means is cooperatively connected with saidfastening clip means and a second structural member releasably securingsaid second structural member to said clip means and to saidfirststructural member in predetermined axial position relative thereto.

lnone form of the present invention, an elongate structural member hasat least one channel means in at leastone side thereof extendinglongitudinally of the structural member and adapted to receive thereinoplel, longitudinally extending channel means on at least one sidethereof adapted to receive oppositely directed flanges on the baseof agenerally hook-shaped clip fastener, with a substantially identicallyconstructed hookshaped clip fastener received in the adjacent channelmeansin said'at least one side of said structural member. The clipfasteners each have a relatively short leg and a relatively-elongateleg, the short leg of each clip fastener having an arcuately shapedsurface adapted to cooperate with .thearcuately shaped surface of theadjacent clip fastener when the clip fasteners are assembled inthechannel means to provide a camming effect wherein the clip fastenersare positively locked in said channel means. The elongate legs of theclip fasteners are disposed adjacent opposite edges of said structuralmember and include snap locking means on the end thereof adapted to bereceived in a cooperating snaplocking recess in an open end of anassociated structural member for locking the structural members togetherwithout requiring the use of separate fasteners or welding or the like.The hook-shaped clip fasteners may be assembled in the channel means atany longitudinal position thereof and need not'be inserted through theend of the channel means.

A third form of the invention is illustrated in FIGS. 12-15. In thisform of the invention, a generally U- shaped fastening clip means withopposite, substantially parallel legs having yieldable projections orinturned flange means thereon is adapted to be releasably snap locked toa first tubular connecting member with the flange-means on the legsreceived in complementary recess means or channel means extending alongthe side of the first connecting member. Outwardly directed, snaplocking shoulder means is on each leg for snap locking cooperation withcomplementary snap locking means on a second tubular connecting memberfor readily releasably joining said second connecting member to saidfirst connecting member. The fastening clip means may be assembled tothe channel means of the first connecting member in any axial positiontherealong and need not be slid into the channel means from one endthereof. Further, the fastening clipmeans illustrated in these figuresdoes not require any separate fasteners to releasably join the first andsecond connecting members together, anda pair of clip means may beassembled to the channel means at the same axial position along thefirst connecting member without interference therebetween.

In FIG. 16, a fourth form of the invention is illustrated and isidentical to the fastening clip means shown in FIGS. 12-l5, except thata separate fastening means such as a screw or rivet or the like is usedfor joining the second connecting member to the fastening clip meansrather than the snap locking shoulder means shown in FIGS. 12-15.

In both the third andfourth forms of the invention, the legs of theU-shaped fastening clip are normally slightly outwardly flared or spreadapart and are urged inwardly toward one another with the flange meansreceived in the channel means when the second connecting member ispositioned on the fastening clip means.

The elongate structural members and clip fasteners may be formed of anysuitable material such as plastic or metal such as aluminum or the like,wherein the clip fasteners may be flexed, thereby permitting sufficientdeformation to move the elements into operative relationship withoutrequiring excessive manual effort.

The structural members and clip fasteners do not require any specialtooling in the manufacture thereof and may besimply manufactured as anextrusion or as a roll-form shape or the like.

Moreover, there is no alignment problem axially of the elements sincethey may be interconnected with one another in any relative axial.relationship with one another.

Even though the structural members and clip fasteners are positivelylocked to one another in the sense that the clip fasteners cannot bewithdrawn through the opening provided in the channel means, the channelmeans and clip fasteners can be separated, if desired,

by sliding the flange means out of the channel means in one form of theinvention or by pivoting the clip fasteners and lifting the flanges outof the channel means in any axial position of the structural member inthe second form of the invention. In the third and fourth forms of theinvention, the clip fastener can be removed from the channel meanswithout sliding it endwise thereof if the second connecting member isfirst removed.

OBJECTS OF THE INVENTION An object of this invention is to provide asnaplocking structural joint assembly, which is simple and inexpensiveas well as light weight in construction and yet which at the same timeis sturdy and easy to use.

Another object of this invention is to provide a snaplocking structuraljoint assembly which is readily manually snapped into operative positionand which positively locks in place and yet which at the same time canbe readily separated when desired.

Still another object of the invention is to provide a snap-lockingstructural joint assembly wherein the elements may be locked into placein any relative axial position, thereby presenting no alignment problemwhen assembling the apparatus.

A still further object of the invention is to provide a snap-lockingstructural joint assembly wherein a twopiece fastening clip means isprovided having means enabling the clip means to be assembled to astructural member at any position along its length and without requiringthe clip means to be inserted into a channel means at one end of thestructural member and slid along its length to a desired operativeposition.

Yet another object is to provide a snap-locking structural jointassembly wherein a fastening clip means is provided having means thereonfor releasably joining together a plurality of connecting memberswithout requiring the use of separate fasteners or the like.

An even further object is to provide a snap-locking structural jointassembly wherein a fastening clip means has snap-locking flange meansthereon for interengagement with snap-locking means on a firstconnecting member and wherein a second connecting member engages saidfastening clip means for maintaining it in locked interengagement withsaid first connecting member.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top perspective view ofone form of the invention showing a pair of structural members locked inassembled relationship by means of a snap-locking fastening clip.

FIG. 2 is an exploded perspective view of the structure shown in FIG. 1.

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 1, showingthe manner in which the opposite legs of the U-shaped fastening clip areflexed inwardly during installation and then locked or snapped intoposition.

FIG. 4 is a sectional view similar to FIG. 3, showing an alternatearrangement of channel means and attachment of a structural member atright angles to the joint assembly.

FIG. 5 is a top perspective view of a structure assembled by means of asnap-locking structural joint assembly of the present invention.

FIG. 6 is a view similar to FIG. 5 of a different structure assembled bymeans of the present invention.

FIG. 7 is an exploded perspective view of a second form of theinvention.

FIG. 8 is a sectional view illustrating the manner in which one of theclip fasteners of FIG. 7 is inserted into the channel means.

FIG. 9 is a top perspective view illustrating the manner in which theclip fasteners in the second form of the invention are oppositelypositioned during assembly.

FIG. 10 is a top perspective view similar to FIG. 9, illustrating theclip fasteners in operative position.

FIG. 11 is a sectional view illustrating the manner in which the clipfasteners in the second form of the invention cooperate to hold thestructural members together in assembled relationship.

FIG. 12 is an exploded perspective view of a third form of snap-lockingstructural joint assembly.

FIG. 13 is a view in section of the joint assembly of FIG. 12 with theparts in locked interengagement.

FIG. 14 is an exploded sectional view of a first connecting member and afastening clip means about to be assembled thereto and showing thenatural, spread apart condition of the legs of the fastening clip means.

FIG. 15 is a side view in elevation of the fastening clip of FIG. 12.

FIG. 16 is a view in section of a fourth form of the invention with apair of second connecting members joined to a first connecting member bya pair of fastening clip means and wherein separate fastening means areused in conjunction with the fastening clip means.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings,wherein like reference numerals refer to like parts throughout theseveral views, a pair of structural elements or tubular connectingmembers 1 and 2 are illustrated in assembled relationship in FIG. 1. Inthis figure, tubular connecting member 1 is shown assembled to tubularconnecting member 2 in a right angular relationship with the end ofmember 1 abutting against the side of member 2 and spaced slightlyinwardly from the end of member 2 along one side thereof. It is to beunderstood that connecting member 1 could be axially positioned at anylocation along connecting member 2. 1

Referring now also to FIGS. 2, 3 and 4, details of construction of thetubular connecting members 1 and 2 and a clip fastener 3 for joining theconnecting members l and 2 together can be seen.

Tubular connecting member 1 is generally rectangular in cross-sectionand has an open end 4 and opposed flat side walls 5, 6, 7, and 8. A pairof slots or recesses 9 and 10 are punched or otherwise suitably formedin the opposite side walls 8. and 6, respectively, and they are spaced apredetermined distance inwardly from the end 4 of tubular member 1.

Tubular member 2 is similarly generally rectangular in cross-section andhas an open end 11 and opposed flat side walls l2, 13, 14 and 15. Theedges of opposite side walls 12 and 14 extend outwardly beyond and atright angles to the plane of walls 13 and 15 and are turned inwardly attheir marginal edges over and parallel to the walls 13 and 15. The edgesterminate short of one another to define channel means 16 and 17 havinga narrowed opening 18 and 19 therein, respectively.

The clip fastener 3 for connecting the tubular members l and 2 togetheris generally U-shaped in crosssection and includes a base portion orwall having a channel 21 extending the width thereof and a boss 22 onthe underside thereof with a pair of opposite, laterally extendingflanges 23 and 25 extending toward and terminating short of the oppositesides of the base portion 20. A pair of upstanding, generally parallellegs 25 and 26 extend from opposite edges of the base portion 20 andterminate at their upper edges in outwardly directed snap-lockingflanges or lips 27 and 28. The outer surfaces or edges of the lips orflanges 27 and 28 are beveled or wedge shaped to define outwardlyfacing, sloping surfaces 29 and 30 to aid in inserting the legs 25 and26 within the open end of a connecting member 1.

In use, the clip member 3 is assembled to the tubular member 2 bysliding the opposed flanges23 and 24 into the recesses defined by thechannel 16 or 17 to a desired position axially of the tubular member,such as shown in FIG. 1. Tubular member 1 is then pushed down over thelegs25 and 26, engaging the sloping surfaces 29 and 30 and flexing thelegs inwardly to the position shown in phantom lines in FIG. 3, thechannel 21 aiding or increasing the ease with which the legs 25 and 26are flexed inwardly. The tubular member 1 is then pushed downwardly overthe legs until the snap-locking flanges 27 and 28 come into registrywith slots 9 and 10 in tubular member 1, at which time the snap-lockingflanges snap into position in the slots positively locking the tubularmembers 1 and 2 together.

In FIG. 4, 21 slightly modified arrangement is shown wherein channelmeans 17 and 16' are provided in adjacent sides 15 and 14 of a channelmember 2. In this arrangement, a pair of tubular members 1 and 2 wouldextend at right angles to one another rather than parallel to oneanotheras in the FIG. 1 embodiment.

Referring now to FIGS. 7 through 11, a modified snap-locking structuraljoint assembly 31 is shown. A tubular connecting member 32 havingagenerally rectangular cross-sectional configuration and opposite flatside walls 33, 34, 35 and 36 has its opposite side walls 33 and 35extended outwardly at 37, 38 and 39, 40 beyond and at rightangles to theplane of side walls 34 and 36, respectively, and then turned inwardly at41, 42 and 43, 44 over the side walls 34 and 36, respectively,at theedges thereof to define relatively shallow recesses or channels 45, 46,47 and 48, at the corners of member 32, respectively.

Relatively short, upstanding walls 49 and 50 extend perpendicularly fromthe center of theside walls 34 and 36, respectively, and a pair ofoppositely directed, laterally extending flanges 51, 52 and 53, 54extend from opposite sides of the free edge of the walls 49 and 50,respectively, toward the opposed flanges 41, 43 and 42, 44,respectively, to define recesses or channel means 55, 56 and 57,58therein substantially twice as deep as the recesses or channel means 45,46, 47 and 48.

The aforesaid wall portions and flanges define a pair of side-byside,longitudinally extending, parallel channels 59, 60 and 61, 62 in thewalls 34 and 36, respectively, having openings 63, 64, 65 and 66thereinto.

, The two-piece clip fastening means comprises a pair of substantiallyidentical, hook-shaped clip fasteners 67 and 68, only one of which willbe described in detail, the same reference numerals primed being appliedto the other. The clipfastener 68 has base portion 69 with a relativelyshort boss 70 extending from the bottom thereof and substantially equalin width to the width of the clip fastener. A pair of flanges 71 and 72extend laterally in opposite directions from the bottom of the boss 70,the flange 72 being substantially twice as wide as the opposite flange71. A relatively short, arcuate wall portion 73 extends upwardly fromone edge of the base portion 70 and an elongate wall portion 74 extendsupwardly from the opposite edge of the base portion 70 generallyparallel to arcuate wall 73. The outer edge of wall 74 terminates in anenlarged portion defining a "snap-locking shoulder or lip 75 with awedge shaped or beveled surface 76 similar to the lip and bevel surfacein the previouslydescribed embodiment.

In use, the clip fasteners 67 and 68 of FIGS. 7 through 11 are assembledto the tubular connecting member 32 by inserting the large flanges 72and 72 through the openings 66 and 65 into the channel means 62 and 61and into the enlarged recesses 58 and 57 adjacent the center of thetubular connecting member 32, with the short, arcuately shaped walls 73and 73 lying over the flanges 54 and 53, respectively, and projectingupwardly therefrom. The longer wall portions 74 and 74' lie over andextend upwardly from the flanges44 and42. The clip fasteners 67 and 68are then pivoted downwardly with flanges 71 and 71 passing through theopenings 61 and 62 and into the recesses48 and 46, respectively. As seenin FIGS. 7 and 8, the clip fasteners 67 and 68 are inserted intothechannels 61 and 62 spaced axially apart from one another along thetubular member 32. The two clip fasteners are then moved axially intoalignment with one another with the arcuate walls 73 and 73' of theopposed fasteners 67 and 68 in abutting relationship with one another.Tubular connecting member 1 is then passed downwardly over the walls 74and 74 just as in the previous embodiment and the engagement of thewalls of tubular connecting member 1 with the beveled surfaces 76 and76' on the walls 74 and 74 of the clip fasteners causes the walls 74 and74' and clip fasteners to be rocked inwardly with the abuttingengagement between the adjacent arcuate walls 73 and 73' effecting acamming action to securely lock the clip fasteners into position and tosecurely hold tubular connecting member 1 to tubular a connecting member32. As can be seen, the two-piece clip fastener permits the clipfasteners and'an associated tubular connecting member 1 to be attachedto tubular connecting member 32 anywhere along its length withoutrequiring the clip fasteners to be inserted into the channel means'atone end of the tubular I connecting member 32. as inthe previousembodiment.

Rather than the channel means being on opposite side walls 34 and 36, asshown, they could be disposed at right angles to one another as depictedin FIG. 4, for example, with reference to the first describedembodiment.

Referring now to FIGS. 12 to 15, a third form of snap-locking structuraljoint assembly is indicated generally at 77 and comprises a firstelongate tubular connecting member 78, a second elongate tubular connecting member 79 and a generally U-shaped fastening clip means 80. V

The first connecting member 78 is substantially rectangular in crosssection and includes opposite, generally parallel spaced side walls 81,82, 83 and 84. The side walls terminate short of one another at theiradjacent edges to define recesses or. channel means 85 at each of thecorners of the connecting member 78. Relatively short wall portions 86and 87 extend perpendicularly from each side wall spaced inwardly fromthe edges thereof and the wall 86 at one edge of a side wall 81, forexample, is connected with the wall 87 at the adjacent edge of a sidewall 84 by a pair of relatively short, mutually perpendicular walls 88and 89. The edge of a side wall and a pair of perpendicular walls 86 and88 define a first channel 90 at one corner of the connecting member andthe opposite edge of the side wall and a pair of walls 87 and 89 definea second channel 91 at the opposite corner of the connecting member. Thechannels 90 and 91 at adjacent edges of a pair of adjacent side walls 81and 84, for example, are perpendicular to one another and open outwardlybeyond the outer edges of the adjacent side walls.

The U-shaped clip fastening means 80 comprises a bight portion 92 bentor deflected downwardly in the middle thereof into the shape of ashallow V and a pair of slightly outwardly flared legs 93 and 94extending from opposite edges of the bight portion 92. Each leg 93 and94 is bent slightly inwardly toward the opposite leg at approximatelythe mid-portion thereof to define a first portion 95 and 96,respectively, extending substantially perpendicularly from the oppositeedges of the bight portion and a second portion 97 and 98, respectively,extending at a slight angle from the portions 96 and 97 toward theopposite leg. A pair of outwardly projecting snap-locking shoulder means99 and 100 are formed on the opposite legs 93 and 94 at the midportionsthereof and include an upwardly and inwardly inclined surface 101 and102, respectively. A pair yieldable projections or inturned flanges 103and 104 are on the bottom edges of the legs 93 and 94 for receipt in apair of channels 90 and 91 at opposite corners of the first connectingmember 78 to joint the fastening clip 80 to the connecting member 78.

The second connecting member 79 includes an open end 105 and oppositespaced side walls 106, 107, 108 and 109. A pair of openings 110 and 111are punched or otherwise suitably formed in a pair of opposite sidewalls 106 and 108 spaced inwardly from the open end thereof forsnap-locking registry with the shoulders 99 and 100 on the fasteningclip 80 to lock the second connecting member 79 to the fastening clip 80and thus to the first connecting member 78.

In use, the fastening clip 80 is positioned with the flanges 103 and 104in alignment with a pair of channel means 90 and 91 as seen in FIG. 14.The second structural member 79 is then slid down over the clip means80, and the opposite side walls 106 and 108 deflect the legs 93 and 94inwardly, urging the flanges 103 and 104 into the channels 90 and 91.The sloping surfaces 101 and 102 cause the side walls 106 and 108 to camthe legs inwardly until the shoulders 99 and 100 come into registry withthe openings 110 and 111, and the legs then flex or snap outwardly andthe shoulders lock behind the bottom edges of the openings 110 and 111.The first and second connecting members 78 and 79 and the clip fastener80 are then securely locked together as seen in FIG. 13.

Referring now to FIG. 16, a fourth form of the invention is illustratedand is substantially identical to the form of the invention illustratedin FIGS. 12 to 15, except that the shoulder means 99 and 100 are omittedfrom the legs 93 and 94 of the clip fastener 80 and the openings 110 and111 are omitted from the side walls 106 and 108 of connecting member79'. A pair of suitable fastening means such as rivets or screws or thelike 112 are extended through the side walls 106 and 108' and the legs93' and 94' to releasably join the second connecting member 79 to theclip fastener and thus to the first connecting member 78. When a pair ofsecond connecting members 79' are joined to a first connecting member 78as seen in FIG. 16, the adjacent edges of the adjacent connectingmembers 79 are in tight abutting contact.

The joint may be secured by crimping the opposite edges of a side wallover the flanges 103 and 104 received in the channels and 91.

FIGS. 5 and 6 illustrate typical structural assemblies which may be madewith the tubular connecting members and clip fasteners of the presentinvention.

The tubular connecting members and the clip fasteners may bemanufactured of any suitable material such as extruded aluminum or thelike or they may be made of plastic or fiberglass and the like.

For certain applications, such as in furniture manufacturing and thelike, wherein a smooth joint is desired, a sectional channel, not shown,may be used to provide a concealed joint covering the die punch slot inthe tubular connecting members.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is therefore illustrative and not restrictive, since thescope of the invention is defined by the appended claims rather than bythe description preceding them, and all changes that fall within themetes and bounds of the claims or that form their functional as well asconjointly cooperative equivalents, are therefore intended to beembraced by those claims.

I claim:

1. A structural joint assembly including a pair of elongate tubularstructural members joined together in right angular relationship,comprising a first elongate tubular structural member of substantiallyrectangularly shaped cross-section and with opposite flat walls andopposite corners, said walls terminating at their longitudinal sideedges short of said corners and includinginset wall portions definingpart of an outwardly opening, closed bottom channel means at thecorners, a pair of opposite walls extending at their opposite side edgesbeyond said inset wall portions and overhanging a portion of saidchannel means and comprising an outer wall of said channel means flushwith a respective one of said pair of walls, so that said channel meansopen outwardly parallel to the plane of a respective one of said pair ofwalls, a second elongate tubular structural member of substantiallyrectangular cross-section and with an open end, a substantially U-shapedfastening clip means with a pair of spaced apart, resiliently yieldablelegs frictionally engaged in said open end with a free end of each legprojecting out of said open end, said U-shaped fastening clip means eachspanning a respective one of said pair of walls from one longitudinaledge to the other longitudinal edge thereof, an inturned flange on thefree end of each leg and engaged in a respective channel means atopposite edges of one of said walls to releasably secure the secondstructural member to the first structural member in right angularrelationship thereto.

2. A structural joint assembly as in claim 1, wherein snap-locking meansare on said fastening clip means and complementary snap-locking meansare on said second structural member, said snap-locking means beingcooperatively interengaged.

3. A snap-locking structural joint assembly as in claim 28, wherein saidU-shaped fastening clip means includes a bight portion and said pair oflegs extend from opposite sides of said bight portion.

4. A snap-locking structural joint assembly as in claim 3, wherein saidlegs are slightly outwardly flared and said flange means extendgenerally perpendicularly therefrom toward one another.

5. A snap-locking structural joint assembly as in claim 4, wherein saidsnap-locking means on said fastening clip means comprises an outwardlyprojecting shoulder means on each leg between the. ends thereof.

6. A snap-locking structural joint assembly as in claim 5, wherein saidsnap-locking means includes an inwardly tapered surface extending fromsaid shoulder means toward said bight portion.

7. A snap-locking structural joint assembly as in claim 6, wherein saidchannel means includes a pair of channels extending at right angles toone another at each corner and opening outwardly beyond the adjacentedge of said flat side walls.

8. A snap-locking structural joint assembly as in claim 7, wherein eachof said flange means is received in a respective one of said pair ofchannels at each opposite edge of one of said flat side walls.

9. A snap-locking structural joint assembly as in claim 8, wherein saidsnap-locking means on said secnd structural member comprises a pair ofopenings in opposite side walls thereof.

10. A snap-locking structural joint assembly as in claim 9, wherein saidshoulder means are received in said openings.

11. A snap-locking structural joint assembly as in claim 10, whereinsaid legs of said U-shaped fastening clip are deflected inwardly towardone another when said second structural member is placed thereover.

12. A snap-locking structural joint assembly as in claim 3, wherein aseparate fastening means is extended through opposite flat sides of saidsecond structural member and through a portion of said fastening clipmeans.

13. A snap-locking structural joint assembly as in claim 12, whereinsaid legs are slightly outwardly flared and said flange means extendgenerally perpendicularly therefrom toward one another.

14. A snap-locking structural joint assembly as in claim 13, whereinsaid channel means includes a pair of channels extending at right anglesto one another at each corner and opening outwardly beyond the adjacentedge of said flat side walls.

15. A snap-locking structural joint assembly as in claim 14, whereineach of said flange means is received in a respective one of said pairof channels at each opposite edge of one of said flat side walls.

16. A snap-locking structural joint assembly as in claim 15, whereinsaid legs of said U-shaped fastening clip are deflected inwardly towardone another when said second structural member is placed thereover.

17. A snap-locking structural joint assembly as in claim 16, whereinsaid separate fastening means comprises a pair of screws extendedthrough a pair of opposite flat sides of said second structural memberand through the legs of said fastening clip means.

1. A structural joint assembly including a pair of elongate tubularstructural members joined together in right angular relationship,comprising a first elongate tubular structural member of substantiallyrectangularly shaped cross-section and with opposite flat walls andopposite corners, said walls terminating at their longitudinal sideedges short of said corners and including inset wall portions definingpart of an outwardly opening, closed bottom channel means at thecorners, a pair of opposite walls extending at their opposite side edgesbeyond said inset wall portions and overhanging a portion of saidchannel means and comprising an outer wall of said channel means flushwith a respective one of said pair of walls, so that said channel meansopen outwardly parallel to the plane of a respective one of said pair ofwalls, a second elongate tubular structural member of substantiallyrectangular cross-section and with an open end, a substantially U-shapedfastening clip means with a pAir of spaced apart, resiliently yieldablelegs frictionally engaged in said open end with a free end of each legprojecting out of said open end, said U-shaped fastening clip means eachspanning a respective one of said pair of walls from one longitudinaledge to the other longitudinal edge thereof, an inturned flange on thefree end of each leg and engaged in a respective channel means atopposite edges of one of said walls to releasably secure the secondstructural member to the first structural member in right angularrelationship thereto.
 2. A structural joint assembly as in claim 1,wherein snap-locking means are on said fastening clip means andcomplementary snap-locking means are on said second structural member,said snap-locking means being cooperatively interengaged.
 3. Asnap-locking structural joint assembly as in claim 28, wherein saidU-shaped fastening clip means includes a bight portion and said pair oflegs extend from opposite sides of said bight portion.
 4. A snap-lockingstructural joint assembly as in claim 3, wherein said legs are slightlyoutwardly flared and said flange means extend generally perpendicularlytherefrom toward one another.
 5. A snap-locking structural jointassembly as in claim 4, wherein said snap-locking means on saidfastening clip means comprises an outwardly projecting shoulder means oneach leg between the ends thereof.
 6. A snap-locking structural jointassembly as in claim 5, wherein said snap-locking means includes aninwardly tapered surface extending from said shoulder means toward saidbight portion.
 7. A snap-locking structural joint assembly as in claim6, wherein said channel means includes a pair of channels extending atright angles to one another at each corner and opening outwardly beyondthe adjacent edge of said flat side walls.
 8. A snap-locking structuraljoint assembly as in claim 7, wherein each of said flange means isreceived in a respective one of said pair of channels at each oppositeedge of one of said flat side walls.
 9. A snap-locking structural jointassembly as in claim 8, wherein said snap-locking means on said secondstructural member comprises a pair of openings in opposite side wallsthereof.
 10. A snap-locking structural joint assembly as in claim 9,wherein said shoulder means are received in said openings.
 11. Asnap-locking structural joint assembly as in claim 10, wherein said legsof said U-shaped fastening clip are deflected inwardly toward oneanother when said second structural member is placed thereover.
 12. Asnap-locking structural joint assembly as in claim 3, wherein a separatefastening means is extended through opposite flat sides of said secondstructural member and through a portion of said fastening clip means.13. A snap-locking structural joint assembly as in claim 12, whereinsaid legs are slightly outwardly flared and said flange means extendgenerally perpendicularly therefrom toward one another.
 14. Asnap-locking structural joint assembly as in claim 13, wherein saidchannel means includes a pair of channels extending at right angles toone another at each corner and opening outwardly beyond the adjacentedge of said flat side walls.
 15. A snap-locking structural jointassembly as in claim 14, wherein each of said flange means is receivedin a respective one of said pair of channels at each opposite edge ofone of said flat side walls.
 16. A snap-locking structural jointassembly as in claim 15, wherein said legs of said U-shaped fasteningclip are deflected inwardly toward one another when said secondstructural member is placed thereover.
 17. A snap-locking structuraljoint assembly as in claim 16, wherein said separate fastening meanscomprises a pair of screws extended through a pair of opposite flatsides of said second structural member and through the legs of saidfastening clip means.